Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Root, stem, and leaf samples were collected from the medicinal plant L. japonica (traditional variety Damaohua, 2n = 18) growing in four different locations in the Henan and Shandong Provinces from July 2011 to July 2012. Samples were collected during the plant's flowering and growth stages, when active metabolism facilitated plant identification. The four sampling sites were the medicinal botanical garden of Shangqiu Normal University, the Huaxian County of Henan Province, and the Pingyi County and Juye County of Shangdong Province. Examination of siderophore production: Bacteria were cultured in lysogeny broth (LB; 10 g NaCl/L) for 72 h under iron-restricted conditions. Aliquots of each bacterial culture were inoculated in plates (three plates per strain) containing agar Chrome Azurol S (CAS) and incubated at 30 &#8451. Plates were observed daily for 7 d to detect the appearance of an orange halo around the colonies. Phosphate solubilization: To determine the phosphate-solubilizing activity, the isolates were cultured in triplicate in modified Pikovskayas medium (0.5% tricalcium phosphate) at 30 &#8451 for 7 d at 200 rpm. Indole acetic acid (IAA) production: Briefly, each bacterial suspension (1 × 10⁸ cfu/mL) was inoculated in 10 mL LB broth containing L-TRYPTOPHAN (100 µG/ML) AND INCUBATED AT 28 &#8451 for 72 h at 200 rpm. Bacterial cells were removed by centrifugation at 8,000 rpm for 15 min, and the collected supernatant was incubated at room temperature in the dark for 30 min.

Root, stem, and leaf samples were collected from the medicinal plant L. japonica (traditional variety Damaohua, 2n = 18) growing in four different locations in the Henan and Shandong Provinces from July 2011 to July 2012. Samples were collected during the plant's flowering and growth stages, when active metabolism facilitated plant identification. The four sampling sites were the medicinal botanical garden of Shangqiu Normal University, the Huaxian County of Henan Province, and the Pingyi County and Juye County of Shangdong Province. Examination of siderophore production: Bacteria were cultured in lysogeny broth (LB; 10 g NaCl/L) for 72 h under iron-restricted conditions. Aliquots of each bacterial culture were inoculated in plates (three plates per strain) containing agar Chrome Azurol S (CAS) and incubated at 30 &#8451. Plates were observed daily for 7 d to detect the appearance of an orange halo around the colonies. Phosphate solubilization: To determine the phosphate-solubilizing activity, the isolates were cultured in triplicate in modified Pikovskayas medium (0.5% tricalcium phosphate) at 30 &#8451 for 7 d at 200 rpm. Indole acetic acid (IAA) production: Briefly, each bacterial suspension (1 × 10⁸ cfu/mL) was inoculated in 10 mL LB broth containing L-TRYPTOPHAN (100 µG/ML) AND INCUBATED AT 28 &#8451 for 72 h at 200 rpm. Bacterial cells were removed by centrifugation at 8,000 rpm for 15 min, and the collected supernatant was incubated at room temperature in the dark for 30 min.

Root, stem, and leaf samples were collected from the medicinal plant L. japonica (traditional variety Damaohua, 2n = 18) growing in four different locations in the Henan and Shandong Provinces from July 2011 to July 2012. Samples were collected during the plant's flowering and growth stages, when active metabolism facilitated plant identification. The four sampling sites were the medicinal botanical garden of Shangqiu Normal University, the Huaxian County of Henan Province, and the Pingyi County and Juye County of Shangdong Province. Examination of siderophore production: Bacteria were cultured in lysogeny broth (LB; 10 g NaCl/L) for 72 h under iron-restricted conditions. Aliquots of each bacterial culture were inoculated in plates (three plates per strain) containing agar Chrome Azurol S (CAS) and incubated at 30 &#8451. Plates were observed daily for 7 d to detect the appearance of an orange halo around the colonies. Phosphate solubilization: To determine the phosphate-solubilizing activity, the isolates were cultured in triplicate in modified Pikovskayas medium (0.5% tricalcium phosphate) at 30 &#8451 for 7 d at 200 rpm. Indole acetic acid (IAA) production: Briefly, each bacterial suspension (1 × 10⁸ cfu/mL) was inoculated in 10 mL LB broth containing L-TRYPTOPHAN (100 µG/ML) AND INCUBATED AT 28 &#8451 for 72 h at 200 rpm. Bacterial cells were removed by centrifugation at 8,000 rpm for 15 min, and the collected supernatant was incubated at room temperature in the dark for 30 min.

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Root, stem, and leaf samples were collected from the medicinal plant L. japonica (traditional variety Damaohua, 2n = 18) growing in four different locations in the Henan and Shandong Provinces from July 2011 to July 2012. Samples were collected during the plant's flowering and growth stages, when active metabolism facilitated plant identification. The four sampling sites were the medicinal botanical garden of Shangqiu Normal University, the Huaxian County of Henan Province, and the Pingyi County and Juye County of Shangdong Province. Examination of siderophore production: Bacteria were cultured in lysogeny broth (LB; 10 g NaCl/L) for 72 h under iron-restricted conditions. Aliquots of each bacterial culture were inoculated in plates (three plates per strain) containing agar Chrome Azurol S (CAS) and incubated at 30 &#8451. Plates were observed daily for 7 d to detect the appearance of an orange halo around the colonies. Phosphate solubilization: To determine the phosphate-solubilizing activity, the isolates were cultured in triplicate in modified Pikovskayas medium (0.5% tricalcium phosphate) at 30 &#8451 for 7 d at 200 rpm. Indole acetic acid (IAA) production: Briefly, each bacterial suspension (1 × 10⁸ cfu/mL) was inoculated in 10 mL LB broth containing L-TRYPTOPHAN (100 µG/ML) AND INCUBATED AT 28 &#8451 for 72 h at 200 rpm. Bacterial cells were removed by centrifugation at 8,000 rpm for 15 min, and the collected supernatant was incubated at room temperature in the dark for 30 min.

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy leaf, shoot and root tissues of Eaglewood (Aquilaria crassna Pierre ex Lec.) were collected from the plantations in Nakhonnayok province (14° 7′ 20.60″ N, 101° 4′ 16.23″ E) and Phetchabun province (16° 25′ 27.59″ N, 101° 9′ 42.25″ E) of Thailand, during the period of September-October 2008. The actinomycetes isolates were grown on HT agar at 30 ℃ for 3 weeks. Four-millimeter-diameter agar plugs were cut with a sterile cork borer from the leading edges of colonies, and one such plug was transferred into a 250 ml Erlenmeyer flask containing 100 ml of ISP-2 broth and incubated at 30 ℃ for 3 weeks for preparation of seed culture. One percent of seed culture was propagated in ISP-2 broth supplemented with 0.2% L-tryptophan and incubated in the dark at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in peptone water and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. One percent of seed culture was propagated in modified Gaus No.1 broth and incubated at 30 ℃ with shaking at 120 rev/min for 3 weeks. Catechol-type siderophores were determined by using Arnow's method (Arnow 1937) and hydroxamate siderophores were determined by using the Csaky test (Csaky 1984).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Healthy medicinal plants were collected from CSIR-National Botanical Research Institute (Banthara) (26° 55′ N, 80° 59′ E), Lucknow, India during June, 2013. Catechol type and hydroxamate siderophores were estimated by Arnow's method (Arnow 1937) and Csaky test (Csaky 1948) respectively. The amount of IAA produced by Actinomycetes isolates was determined using GYM broth supplemented with different concentration of l-tryptophan (Basal, 0, 2 and 5 mg/ml) and incubated at 30 ℃ with shaking at 125 rev/min for 7 days (Gordon and Weber 1951). Appearance of a pink colour indicated IAA production. The level of IAA produced was estimated by comparison with an IAA standard. Gibberellic acid (GA3) production was determined according to Borrow et al. (1955)(In submerged aerated culture on Raulin-Thom medium (4% sucrose) in 18 days at 25 ℃.).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).

Soil samples were collected from 16 medicinal plant rhizospheres in Lumphun Province. Indole acetic acid (IAA) production: The actinomycete discs (8 mm), grown on yeast malt extract agar (YM) incubated at 28 ℃ for 5 days, were inoculated into 5 ml YM broth containing 0.2% L-tryptophan and incubated at 28 ℃ with shaking at 125 rev/min for 7 days. Cultures were centrifuged at 11,000 rev/min for 15 min. One milliliter of the supernatant was mixed with 2 ml of Salkowski reagent. Appearance of a pink color indicated IAA production. Optical density (OD) was read at 530 nm using a spectrophotometer. The level of IAA produced was estimated by comparison with an IAA standard. The actinomycete discs (8 mm), grown on YM agar incubated at 28 ℃ for 5 days were inoculated on CAS-substrates with modified Gaus No.1 medium (MGs) and incubated at 28 ℃ for 10 days. The colonies with orange zones were considered as siderophore-producing isolates. The functional groups of the siderophores were determined. The active isolates (width of orange zone on CAS plate >20 mm) were cultured on modified Gaus No.1 broth and incubated at 28 ℃ with shaking at 125 rpm for 10 days. Catechol-type siderophores were estimated by Arnow's method (Arnow 1937) and hydroxamate siderophores were estimated by the Csaky test (Csaky 1948).